Combination fan-flywheel-pulley assembly and method of forming

ABSTRACT

A fan-flywheel-pulley assembly for use in conjunction with an electric motor. The assembly may include a pulley positioned about a central axis. The assembly may also include a flywheel coupled to the pulley and positioned about the central axis, the flywheel including an outer circumferential flywheel surface partially forming a plurality of circumferentially spaced openings. The flywheel may also include a baffle that extends circumferentially in close proximity to a cylindrical wall unit of the motor from an inner diameter to an outer diameter to limit a gap between the baffle and the cylindrical wall unit. Further, the assembly may also include a radial fan disposed within the flywheel including a plurality of blades extending at least from the flywheel inner diameter to the outer diameter each opening is positioned between each adjacent fan blade. The pulley, the flywheel, and the radial fan may be integrally formed.

TECHNICAL FIELD

[0001] This invention relates generally to a flywheel assembly. Moreparticularly, this invention relates to a combinationfan-flywheel-pulley assembly with an integral baffle, used inconjunction with an electric motor.

BACKGROUND

[0002] Flywheel assemblies are typically coupled to an armature shaft ofa motor to maintain rotational speed of the motor by virtue of theinertia of the flywheel. In addition, fans have been mounted to a motorto cool the motor. Pulley systems are also used to transfer power fromthe shaft of the motor to other components. Combinationfan-flywheel-pulley assemblies typically include several componentsjoined together, using a process such as staking, to create the fan,flywheel, and pulley assembly. Once such assembly is disclosed in U.S.Pat. No. 5,735,669 to Niemela.

[0003] Known fan-flywheel-pulley assemblies may have severalshortcomings. The combination assemblies can be difficult tomanufacture. In addition, the need for increased inertia from theflywheel requires an increase in the diameter of the flywheel, therebyincreasing the size of any housing covering the assembly. Also, theperformance of the fan can vary depending on the type of blade used tocreate the fan and depending on how efficiently the fan can circulateair through the motor.

[0004] Accordingly, there is a need for a combinationfan-flywheel-pulley assembly that is simple to manufacture, maintains alow profile, and is efficient in cooling the motor.

SUMMARY

[0005] This invention relates generally to a flywheel assembly. Moreparticularly, this invention relates to a combinationfan-flywheel-pulley assembly with an integral baffle, used inconjunction with an electric motor.

[0006] According to a first aspect of the invention, afan-flywheel-pulley assembly for use in conjunction with an electricmotor is provided, the assembly generally comprising a pulley positionedabout a central axis; a flywheel coupled to the pulley and positionedabout the central axis, the flywheel including a baffle extendingcircumferentially over and in close proximity to a cylindrical wall unitof the motor, the baffle surrounding the motor to reduce air leakagebetween the baffle and the cylindrical wall unit; and a fan coupled tothe flywheel including a plurality of radial blades and positioned aboutthe central axis.

[0007] According to another aspect of the invention, afan-flywheel-pulley assembly for use in conjunction with an electricmotor may generally comprise a pulley positioned about a central axis; aflywheel coupled to the pulley and positioned about the central axis,the flywheel including an outer circumferential flywheel surface atleast partially defining a plurality of circumferentially spacedopenings, and wherein a portion of the flywheel extendscircumferentially about a cylindrical wall unit of the motor from aninner diameter to an outer diameter, wherein the portion creates abaffle positioned in close proximity to the cylindrical wall unit tolimit a gap between the baffle and the cylindrical wall unit; and aradial fan disposed within the flywheel and positioned about the centralaxis including a plurality of blades, wherein each of the plurality ofblades extends at least from the inner diameter to the outer diameter ofthe flywheel so that one of the plurality of openings are positionedbetween each adjacent blade of the plurality of blades. The pulley, theflywheel, and the radial fan may be integrally formed.

[0008] According to yet another aspect of the invention, an electricmotor is provided comprising a shaft rotatably mounted about a centralaxis and a housing enclosing the motor and including a cylindrical wallunit having a front plate connected to a front end of the cylindricalwall unit and a back plate connected to a back end of the cylindricalwall unit. Also included is an integral fan-flywheel-pulley assemblycoupled to the shaft including a pulley including a circumferentialpulley surface extending along the central axis; a flywheel coupled tothe pulley and positioned about the central axis and extendingcircumferentially from an inner diameter to an outer diameter, theflywheel including an outer circumferential flywheel surface at leastpartially defining a plurality of circumferentially spaced openings andfurther including a baffle extending over and in close proximity to thecylindrical wall unit of the motor to reduce leakage of air between thebaffle and the cylindrical wall unit and thereby improve air flowthrough the motor; and a radial fan disposed within the flywheel andpositioned about the central axis including a plurality of blades,wherein each of the plurality of blades are curved and extend at leastfrom the inner diameter to the outer diameter of the flywheel so thatone of each of the plurality of circumferentially spaced openings arepositioned between each adjacent blade of the plurality of blades, andwherein the radial fan draws air through the motor. The pulley, theflywheel, and the radial fan may be integrally formed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1 is a front plan view of an exemplary combinationfan-flywheel-pulley assembly in accordance with the present invention.

[0010]FIG. 2 is a front perspective view of the assembly of FIG. 1.

[0011]FIG. 3 is a back plan view of the assembly of FIG. 1.

[0012]FIG. 4 is a back perspective view of the assembly of FIG. 1.

[0013]FIG. 5 is a side plan view of the assembly of FIG. 1.

[0014]FIG. 6 is a cutaway front perspective view of the assembly of FIG.1 showing the fan blades.

[0015]FIG. 7 is a side plan view of the assembly of FIG. 1 shown coupledto a motor in accordance with an example embodiment of the invention.

[0016]FIG. 8 is a cross-sectional view taken along line 7-7 of FIG. 7showing the assembly and the motor.

[0017]FIG. 9 is a front perspective of a second embodiment of anexemplary fan assembly in accordance with the present invention.

[0018]FIG. 10 is a back perspective of the fan assembly shown in FIG. 9.

DETAILED DESCRIPTION

[0019] This invention relates generally to a flywheel assembly. Moreparticularly, this invention relates to a combinationfan-flywheel-pulley assembly with an integral baffle, used inconjunction with an electric motor. While the present invention is notso limited, an appreciation of the various aspects of the invention willbe gained through a discussion of the examples provided below.

[0020] An example fan-flywheel-pulley assembly made in accordance withthis invention generally includes a pulley positioned about a centralaxis, a flywheel assembly coupled to the pulley and positioned about thecentral axis, and a fan including a plurality of radial blades generallydisposed within the flywheel. The flywheel assembly includes a baffleextending circumferentially over and in close proximity to a cylindricalwall unit of an electric motor.

[0021] Referring now to FIGS. 1-5, an exemplary fan-flywheel-pulleyassembly 100 is shown in accordance with the present invention. Thefan-flywheel-pulley assembly 100 generally comprises a fan 203, aflywheel 101, and a pulley 102. The fan 203, flywheel 101, and pulley102 may be integrally coupled to form the assembly 100, as described indetail below.

[0022] The pulley 102 of the assembly 100, shown best in FIG. 2,includes an outer pulley diameter 120 with an outer pulley surface 121and an inner pulley diameter 130 with an inner pulley surface 131. Theouter pulley surface 121 is grooved, with an inner groove diameter 125.The grooves on the outer surface 121 provide a surface with increasedfrictional grip to allow a belt, such as, for example, a standard orpoly-v belt or a cog-belt, or other device to attach to the outersurface 121. Alternatively, the outer pulley surface 121 may not need tobe grooved. The inner pulley diameter 130 defines an aperture 140. Theinner pulley surface 131 is threaded, with a thread diameter 135. Thethreads on the inner pulley surface 131 allow the pulley 102 to bethreaded onto an armature shaft of a motor (not shown) extending throughthe aperture 140. Alternatively, the inner pulley surface 131 may alsobe, for example, keyed, tapered, or configured to be press-fit onto ashaft of a motor.

[0023] The flywheel 101, shown best in FIGS. 2 and 4, is coupled to thepulley 102 and includes an outer flywheel diameter 110 and an innerflywheel diameter 310. The flywheel 101 generally defines an outerflywheel surface 210. In addition, the flywheel 101 includes a baffleportion 420 with an inner baffle diameter 320, an outer baffle surface220, and an inner baffle surface 410. The outer flywheel surface 210partially defines, along with a portion of the fan 203 described below,a plurality of openings 230 circumferentially spaced along the outerflywheel surface 210. A surface 115 of the flywheel 101 may preferablybe, although need not be, solid and continuous.

[0024] The fan 203, shown best in FIGS. 3 and 4, is illustrated in theexample assembly 100 as being generally disposed within the flywheel 101and includes a plurality of blades 235. Outermost blade tips 236 ofadjacent blades 235 are positioned on the outer flywheel diameter 210 topartially define each opening 230 along the outer flywheel diameter 210.An innermost tip 337 of each blade 235 may preferably, but need not,extend towards the aperture 140 past the inner baffle diameter 320. Theblades 235 are also preferably curved, but may also be straight. The fan203 is preferably a radial, or centrifugal fan, as opposed to an axialfan. A radial fan is preferable because the radial fan is best adaptedto handle the high-pressure aerodynamic load of a motor.

[0025] Referring now to FIG. 6, a cutaway front perspective view of theassembly 100 is provided with a portion of the flywheel 101 removed tobetter show the components of the fan 203. As shown, the outermost bladetip 236 of each blade 235 extends to the outer flywheel surface 210,thereby defining, along with a portion of the outer flywheel surface210, each adjacent opening 230.

[0026] In FIGS. 7 and 8, the assembly 100 is shown coupled to an examplemotor 700 in accordance with the present invention. The motor 700includes a cylindrical wall unit or housing 710 as well as a front 715and a rear 720. A front plate 716 may be connected to the front 715 ofthe motor 700, and a back plate 719 may be connected to the rear 720 ofthe motor 700. As illustrated, the assembly 100 is coupled to the motor700 adjacent the front 715 of the motor 700. However, the assembly 100may alternatively be coupled to the motor 700 adjacent the rear 720.

[0027] Referring now to the cross-sectional view in FIG. 8 taken alongline 7-7 of FIG. 7, the threaded inner pulley surface 131 of theassembly 100 is threaded onto an armature shaft 820 of the motor 700. Inthis configuration, the assembly 100 rotates as the armature shaft 820of the motor 700 rotates. The flywheel 101 of the assembly 100, throughits inertia, stabilizes and maintains the rotational speed of the shaft820. The pulley 102 of the assembly 100 can be connected to a belt orother component to transfer the rotational energy generated by the motor700 to another component in the system. The fan 203 of the assembly 100draws air from the rear 720 of the motor 700 through the housing 710.The air then exits through the openings 230. The air forced through thehousing 710 functions to cool the internal components of the motor 700.

[0028] As shown in FIG. 8, the flywheel 101 of the assembly 100,specifically the baffle portion 420, extends over the housing 710 of themotor 700. The inner baffle diameter 320 is selected so that the innerbaffle surface 410 extends in close proximity to the housing 710. Thegap 810 between the inner baffle surface 410 and the housing 710 isgenerally small and is preferably equal to or less than ¼ inch, althoughother sizes are also possible. In this configuration, the inner bafflesurface 410 is in close proximity to the housing 710 to reduce anyleakage of air through gap 810. As the leakage is reduced, air is moreefficiently forced from the rear 720, through the housing 710, along theblades 235, and out the openings 230 in the assembly 100, therebycooling the motor 700 more efficiently.

[0029] The baffle portion 420 of the flywheel 101 extending over themotor 700 also provides additional inertia. To create a flywheel thatgenerates additional inertia, it is necessary to add more mass to theflywheel. This can be accomplished by “building out” a flywheel byincreasing the outer flywheel diameter 110, or, as disclosed in thisinvention, extending the flywheel so that it extends further over themotor. In some applications, it is preferable to minimize the profile,or outer diameter, of the flywheel. In these cases, inertia can beincreased, in accordance with the present invention, by increasing theinner and outer baffle surfaces 220 and 410 to extend the assembly 100further towards the rear 720 of the motor 700. In this manner, theassembly 100 is designed with a greater mass and therefore greaterinertia, while still minimizing the profile, or outer diameter 110, ofthe assembly 100.

[0030] For example, for an application such as a treadmill, it isnecessary to provide an assembly that has sufficient inertia to maintaina constant rotational speed but still maintain a low profile to fit intoan aesthetically-pleasing treadmill housing. Therefore, the assembly 100made in accordance with the present invention provides additionalinertia via the baffle portion 420, while still maintaining a lowprofile to fit into a lower profile treadmill housing.

[0031] The exemplary assembly 100 may be made using a variety ofmethods, such as, for example, die casting, sand casting, plastermolding, metal injection molding, etc. The assembly 100 is preferablyformed as a single, integral unit, although the assembly 100 can beformed of various pieces joined together to create an integral unit. Asused herein, “integrally formed” means formed as a single unit out of aunitary piece of material, such as by molding.

[0032] An example method of making the assembly 100 may generallyinclude: (1) providing a mold made of known materials such as sand orplaster; (2) introducing a molten material into the mold; (3) allowingthe molten material to harden a predetermined amount of time to form themolded unit; (4) stripping the molded unit from the mold; and (5)performing various finishing processes such as cleaning, trimming,machining, and/or balancing the molded unit. Other methods of formingthe assembly 100 can also be used without departing from the scope ofthe invention.

[0033] The exemplary assembly 100 may be made of a variety of materials.Generally, the assembly 100 may be made of any castable metal, such as,for example, iron, aluminum, zinc, magnesium, etc. Other materials mayalso be used depending on the desired use for the assembly 100.

[0034] A second embodiment of an exemplary assembly 900 made inaccordance with the present invention is shown in FIGS. 9 and 10. Theassembly 900 is similar to the assembly 100. However, the assembly 900is designed to function more as a light, highly-efficient fan.

[0035] The assembly 900 includes a hub 910. The hub 910 may or may notfunction as the pulley system described in reference to the assembly100. Alternatively, the hub 910 may be removed from the assembly 900 ifnot needed.

[0036] A plurality of blades 940 form a fan 925 disposed within theassembly 900. A blade tip 945 of each of the plurality of blades 940extends to an outer diameter 905 of the assembly 900, and adjacent tips945 define a plurality of openings 930 circumferentially spaced alongthe assembly 900 outer diameter 905.

[0037] The assembly 900 includes a baffle portion 920. The baffleportion 920 is constructed to extend in close proximity to a housing ofa motor (not shown) onto which the assembly 900 is mounted. In thisconfiguration, as explained above, the baffle portion 920 may reduceleakage of air between the baffle portion 920 and the housing of themotor, thereby increasing the efficiency of the fan. The assembly 900may therefore be advantageous in applications that require little or noadditional inertia but would benefit from the high efficiency of the fan925.

[0038] The assembly 900 may be made using a variety of processes, forexample, injection or compression molding. If injection molding is used,the steps for forming the assembly 900 may generally include: (1)providing a mold with a cavity; (2) injecting the cavity with a polymerunder pressure; (3) allowing the polymer to solidify; (4) unclamping themold; (5) removing the molded unit; and (6) performing various finishingprocesses such as trimming flash. Other processes may also be used.

[0039] The assembly 900 may be made using a variety of materials.Preferably, the assembly 900 is made of a light material, such as apolymer, although other materials, such as lighter castable metals(e.g., aluminum), may also be used.

[0040] The above specification, examples and data provide a completedescription of the manufacture and use of the composition of theinvention. Since many embodiments of the invention can be made withoutdeparting from the spirit and scope of the invention, the inventionresides in the claims hereinafter appended.

What is claimed is:
 1. A fan-flywheel-pulley assembly for use inconjunction with an electric motor, the assembly comprising: a pulleypositioned about a central axis; a flywheel coupled to the pulley andpositioned about the central axis, the flywheel including a baffle withan inner baffle diameter extending circumferentially over and in closeproximity to a cylindrical wall unit of the motor, the bafflesurrounding the motor to reduce air leakage between the baffle and thecylindrical wall unit; and a fan coupled to the flywheel including aplurality of radial blades and positioned about the central axis.
 2. Thefan-flywheel-pulley assembly of claim 1, wherein the flywheel extendscircumferentially from an inner diameter to an outer diameter, theflywheel including an outer circumferential flywheel surface at leastpartially defining a plurality of circumferentially spaced openings. 3.The fan-flywheel-pulley assembly of claim 2 wherein the fan is disposedwithin the flywheel and wherein each of the plurality of radial bladesextends at least from the inner baffle diameter to the outer diameter ofthe flywheel so that one of each of the plurality of openings arepositioned between each adjacent blade of the plurality of blades. 4.The fan-flywheel-pulley assembly of claim 3, wherein each of theplurality of radial blades extends past the inner baffle diametertowards the central axis.
 5. The fan-flywheel-pulley assembly of claim1, wherein the inner baffle diameter engages the cylindrical wall unitof the motor.
 6. The fan-flywheel-pulley assembly of claim 5, wherein agap between the baffle and the cylindrical wall unit is less than ¼inch.
 7. The fan-flywheel-pulley assembly of claim 1, wherein each ofthe plurality of radial blades is curved.
 8. The fan-flywheel-pulleyassembly of claim 1, wherein the baffle rotates with the assembly. 9.The fan-flywheel-pulley assembly of claim 1, wherein the pulley, thefan, and the flywheel are integrally formed.
 10. The fan-flywheel-pulleyassembly of claim 9, wherein the assembly is molded.
 11. Thefan-flywheel-pulley assembly of claim 1, wherein the baffle extends overthe cylindrical wall unit of the motor to increase an amount of inertiagenerated by the assembly.
 12. A fan-flywheel-pulley assembly for use inconjunction with an electric motor, the assembly comprising: a pulleypositioned about a central axis; a flywheel coupled to the pulley andpositioned about the central axis, the flywheel including an outercircumferential flywheel surface at least partially defining a pluralityof circumferentially spaced openings, and wherein a portion of theflywheel extends circumferentially about a cylindrical wall unit of themotor from an inner diameter to an outer diameter, wherein the portioncreates a baffle positioned in close proximity to the cylindrical wallunit to limit a gap between the baffle and the cylindrical wall unit;and a radial fan disposed within the flywheel and positioned about thecentral axis including a plurality of blades, wherein each of theplurality of blades extends at least from the inner diameter to theouter diameter of the flywheel so that one of the plurality of openingsare positioned between each adjacent blade of the plurality of blades;wherein the pulley, the flywheel, and the radial fan are integrallyformed.
 13. The fan-flywheel-pulley assembly of claim 12, wherein theassembly is molded.
 14. The fan-flywheel-pulley assembly of claim 12,wherein the baffle extends over the cylindrical wall unit of the motorto increase an amount of inertia generated by the assembly.
 15. Thefan-flywheel-pulley assembly of claim 12, wherein the gap between thebaffle and the cylindrical wall unit is less than ¼ inch.
 16. Thefan-flywheel-pulley assembly of claim 12, wherein the baffle rotateswith the assembly.
 17. An electric motor comprising: a shaft rotatablymounted about a central axis; a housing enclosing the motor andincluding a cylindrical wall unit having a front plate connected to afront end of the cylindrical wall unit and a back plate connected to aback end of the cylindrical wall unit; and an integralfan-flywheel-pulley assembly coupled to the shaft including: a pulleyincluding a circumferential pulley surface extending along the centralaxis; a flywheel coupled to the pulley and positioned about the centralaxis and extending circumferentially from an inner diameter to an outerdiameter, the flywheel including an outer circumferential flywheelsurface at least partially defining a plurality of circumferentiallyspaced openings and further including a baffle extending over and inclose proximity to the cylindrical wall unit of the motor to reduceleakage of air between the baffle and the cylindrical wall unit andthereby improve air flow through the motor; and a radial fan disposedwithin the flywheel and positioned about the central axis including aplurality of blades, wherein each of the plurality of blades are curvedand extend at least from the inner diameter to the outer diameter of theflywheel so that one of each of the plurality of circumferentiallyspaced openings are positioned between each adjacent blade of theplurality of blades, and wherein the radial fan draws air through themotor; wherein the pulley, the flywheel, and the radial fan areintegrally formed.
 18. The electric motor of claim 17, wherein thebaffle extends over the cylindrical wall unit of the motor to increasean amount of inertia generated by the assembly.
 19. The electric motorof claim 17, wherein a gap between the baffle and the cylindrical wallunit is less than ¼ inch.
 20. The electric motor of claim 17, whereinthe baffle rotates with the assembly.